The present invention relates to small electric motors and more particularly to synchronous motors and step-by-step motors comprising a rotor with permanent magnet, magnetized along a plurality of pairs of poles, fast with a shaft rotating in two bearings supported by a stator. The stator is constituted by an assembly of two coils and of polar pieces disposed inside a carcase of magnetic material.
Motors of this type are wide-spread and widely used in industry. They are mass-produced and production thereof has been optimalized by reducing the number of their constituents to the strict minimum and by using identical pieces whenever possible. This is the case, for example, of the coils, if there are several of them, and of the polar pieces.
In order to reduce the cost price of this type of motor further, they must be studied with a view to saving time during manufacture, by simplifying assembly thereof and reducing the number of the operations on separate work stations.
It is an object of the present invention to produce such a motor. In fact, the various constituents of this motor have been studied and arranged to facilitate assembly therof on a production line. Manufacture consists in assembling its various constituents by stacking so as to make a solid sub-assembly which is easy to transfer thereafter onto an electric welding station. One operation suffices to weld, simultaneously, two side elements disposed on either side of its magnetic carcase to close it definitively.